The present invention relates to a tape reel assembly for a data storage tape cartridge. More particularly, it relates to a tape reel assembly configured to improve cartridge performance and minimize damage to an associated metallic washer during use.
Data storage tape cartridges have been used for decades in the computer, audio and video fields. The data storage tape cartridge continues to be an extremely popular form of recording large volumes of information for subsequent retrieval and use.
A data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel assembly and a length of magnetic storage tape. The storage tape is wrapped about a hub portion of the tape reel assembly and is driven through a defined tape path by a driving system. The housing normally includes a separate cover and base, the combination of which forms an opening (or window) at a forward portion thereof for allowing access to the storage tape by a read/write head upon insertion of the data storage tape cartridge into a tape drive. This interaction between storage tape and head may take place within the housing (for example, with a mid-tape load design), or the storage tape may be directed away from the housing to an adjacent area at which the read/write head is located (for example, with a helical drive design or a leader block design). Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, a single tape reel assembly is normally employed. Conversely, where the tape cartridge/drive system is designed to provide head/storage tape interaction within or very near the housing, a two- or dual-tape reel assembly configuration is typically utilized.
Regardless of the number of tape reel assemblies associated with a particular data storage tape cartridge, the tape reel assembly itself is generally comprised of three basic components; namely, an upper flange, a lower flange, and a hub body. The hub body forms an outer, tape-winding surface about which the storage tape is wound. The flanges are disposed at opposite ends of the hub, and are spaced to approximate the height of the storage tape. With most available tape reel assemblies, the hub body includes a cylindrical hub ring and a radial engagement section or web. The hub ring defines the tape-winding surface and forms a central opening sized to slidably receive a brake body. The engagement section extends radially inwardly from the hub ring at one end thereof. The engagement section typically includes an interior, toothed surface formed to selectively engage teeth formed on the brake assembly to "lock" the tape reel assembly to the housing. The brake assembly is accessible through a passage formed in the engagement section. Thus, upon insertion into a tape drive, a post or spindle portion of a drive hub extends through the passage and contacts the brake assembly, directing the brake assembly from the locked position.
To facilitate engagement between the tape reel assembly and the drive hub, the tape reel assembly typically further includes a metallic washer or ring, whereas the drive hub includes a corresponding magnet. The metallic ring is secured to an outer surface of the engagement section, generally axially aligned with the tape-winding surface. The magnet is reciprocally located along the drive hub. So as to maximize magnetic force between the metallic ring and the magnet, the metallic ring is formed to be as large as possible. In this regard, the metallic ring typically has an inner diameter smaller than a diameter of the passage formed in the engagement section. As a result, during use, the inner diameter surface of the metallic ring is the surface proximate or "closest" to the drive post as the post is inserted into, and retracted from, the tape reel assembly.
The hub body and the metallic ring are normally formed to satisfy tight tolerance requirements. However, inherent manufacturing/assembly constraints may result in the metallic ring not being precisely axially aligned with the hub body, and in particular the tape-winding surface. This variability in co-axial alignment between the metallic ring and the tape-winding surface may negatively affect performance of the data storage tape cartridge due to changes in relative velocity as the hub rotates. In addition, during tape drive engagement, because the inner diameter surface of the metallic ring is effectively "exposed" relative to the drive hub post, it is possible that the post will undesirably contact an edge of the misaligned metallic ring. Alternatively, the drive itself may be misaligned, again resulting in the post undesirably contacting the "exposed" metallic ring. Contact between the metallic ring and the drive hub post may damage one or both of the components. In addition, as the post is retracted from the tape reel assembly, the post may contact and pull or force the metallic ring away from the tape reel hub. Beyond the obvious damage to the tape reel assembly, the removed metallic ring may remain affixed to the drive hub magnet, requiring the user to stop tape drive operations while waiting for a service technician to repair the tape drive.
Data storage tape cartridges are important tools used to maintain vast amounts of information. To remain competitive, data storage tape cartridge manufacturers must continually improve cartridge performance while reducing manufacturing costs. To this end, use of readily available metallic rings does optimize costs, but may lead to unexpected cartridge damage and/or alignment concerns. Therefore, a need exists for a tape reel assembly including a metallic ring guard.